1. Field
The present invention relates generally to architectural paints and, in particular, to architectural paint colorants.
2. Description of the Related Art
Architectural paint (xe2x80x9chouse paintxe2x80x9d) is commonly provided in various colors. Paint color groups have been developed to provide a selection of architectural paint colors to consumers.
Paint colors are sometimes referenced with respect to systems for arranging and describing color, generally referred to as color-order systems. One well-known color-order system is the Munsell system. According to the Munsell system, all possible colors are characterized by three attributes: hue, value, and chroma. Hue is the attribute of color which is commonly described by words such as xe2x80x9cred,xe2x80x9d xe2x80x9cyellow,xe2x80x9d xe2x80x9cgreen,xe2x80x9d xe2x80x9cblue,xe2x80x9d xe2x80x9cpurple,xe2x80x9d etc. Value is the attribute of color which is described by the words xe2x80x9clight,xe2x80x9d xe2x80x9cdark,xe2x80x9d etc. Chroma is the attribute of color which is described by the words xe2x80x9cbright,xe2x80x9d xe2x80x9cdull,xe2x80x9d etc. For example, the colors of a tomato and a brick may be equal in hue and value, yet the colors are not identical. The difference is that the tomato is brighter, having a higher chroma.
Munsell color space is a three-dimensional space including and describing visual relationships between colors. This color space is based on a collection of actual physical samples arranged so that adjacent samples represent distinct intervals of visual color perception. Although based on physical samples, Munsell color space is theoretically capable of describing all possible colors. According to the Munsell system, color space is described with respect to three dimensions: hue, value, and chroma. Theoretically, the Munsell location of every possible color can be described by three coordinates, corresponding to the hue, value, and chroma of the given color. Although in theory Munsell color space is capable of describing all colors, it is understood that it may not be possible to create physical samples of all of the colors which could theoretically fit within Munsell color space. In particular, not all theoretical colors within the perceived Munsell color space can be made into paints.
Within Munsell color space, a vertical axis, known as the value axis, represents color value. In other words, the value (lightness/darkness) of color is determined by the vertical position within color space. Color becomes lighter as the vertical position increases. The hue of color is determined by the angular position about the vertical value axis. The various hues, i.e., shades of red, yellow, green, blue, purple, etc., are represented by vertical planes extending radially from the value axis. Moreover, every angular position about the axis, from 0xc2x0 to 360xc2x0, represents a different hue. The chroma (brightness/dullness) of color is determined by the radial distance from the value axis. Color is dull (gray) near the axis and becomes brighter, or more xe2x80x9cchromatic,xe2x80x9d as the radial distance from the value axis increases.
The Munsell system is one of a number of color-order systems based on actual physical samples. Another class of color-order systems are not based on physical samples. One of the most important of these systems is the CIE System (Commission International de l""Eclairage or International Commission on Illumination). The premise of the CIE System is that the stimulus for color is provided by a proper combination of a source of light, an object, and an observer. The CIE System describes color with reference to a standard source of illumination and a standard observer.
One widely used non-linear transformation of the CIE System is CIELAB, an opponent-type space in which color is described by the three coordinates L, a, and b. In CIELAB space, L is the lightness of color (similar to Munsell value), a is a redness-greenness coordinate, and b is a yellowness-blueness coordinate. Several color-order systems exist within CIELAB space. One such color-order system is D65 CIELAB.
Paints of various colors are generally formed by mixing one or more liquid paint colorants with a paint base. Paint color can be varied by using a different combination of paint colorants, or by changing the concentration of one or more of the colorants in the paint. Paint colorants are formed by blending one or more pigments into what the industry refers to as a xe2x80x9cgrinding liquid,xe2x80x9d a liquid grinding medium. The coloring power of a paint colorant can be varied by changing the pigment concentrations of the constituent pigments in the colorant.
Existing methods for producing paints for customers at a retail site commonly utilize a mixing device having a plurality of spouts, each adapted to eject one or more drops of a particular paint colorant into a paint base. Accordingly, a customer may select a desired quantity of paint having a desired paint color. The desired paint color has known ratios of various paint colorants to a paint base. Typically, a paint technician will operate the mixing device so as to mix the various quantities of the constituent paint colorants with a quantity of the paint base to produce the desired quantity of the selected paint color. A limitation of this method is that it may be difficult to accurately produce the selected paint color. The smallest quantity of any colorant that the mixing device can eject is a drop of about {fraction (1/96)} of an ounce. Some mixing devices are limited to drops of {fraction (1/48)} of an ounce. Thus, the amount of any given constituent colorant in the produced paint will be a multiple of drops. However, it may be desirable to blend an amount of a particular colorant which is not exactly equal to a multiple of drops. This xe2x80x9cone-dropxe2x80x9d limitation of the mixing device causes some inherent imprecision in the mixing of colorants, which may result in the produced paint having a color which is slightly different than that which was selected by the customer. 
Accordingly, it is a principle object and advantage of the present invention to overcome some or all of these limitations and to provide a specialized paint colorant facilitating the accurate production of paint colors throughout a given architectural paint color space.
The present invention provides a xe2x80x9cneutral paint colorantxe2x80x9d to aid in the development of paint colors throughout color space. In particular, the neutral paint colorant, or simply neutral colorant, may be added to a paint to decrease the paint""s chroma while maintaining its hue substantially constant. Advantageously, the neutral colorant may be added to highly chromatic colors to develop duller colors that may be more suitable for some purposes. This is especially useful in the architectural paint environment in which duller, less chromatic colors are used more often than brighter, more chromatic colors.
One may readily determine the colorant compositions of the architectural paint colors developed with the aid of the neutral colorant of the invention. Each paint color comprises a mixture of prime colorants, neutral colorant, and paint base. The ratios of each of these constituents to the whole mixture are determined as described below. The colorant compositions of various paint colors may be recorded in a storage medium for use at a retail site. Advantageously, a system is implemented which permits a consumer to select a paint color and then retrieves the composition of the selected paint color. The composition may be fed to an automated paint production apparatus or may be transmitted to a paint technician who will produce the selected paint color.
In one aspect, the present invention provides a method of forming a neutral paint colorant, comprising the following steps: A first colorant is blended with a paint base to form a paint having a chroma substantially equal to zero. A quantity of one of the first colorant or the paint base is added to the paint, to vary the value of the paint. The chroma of the paint is then measured. If the chroma of the paint is not substantially equal to zero, one or more offsetting colorants are added to the paint to reduce the chroma of the paint so that it is substantially equal to zero. The neutral paint colorant comprises a mixture of the first colorant and the offsetting colorants. The composition of the neutral colorant is determined by the relative amounts of the first colorant and the offsetting colorants which are in the paint.
In another aspect, the present invention provides a paint colorant comprising a mixture of pigments blended with a grinding liquid. The colorant is configured to be added to a first paint to form a second paint, wherein the chroma of the second paint is less than the chroma of the first paint, and the hue of the second paint is substantially the same as the hue of the first paint.
In another aspect, the present invention provides a paint colorant comprising a mixture of pigments blended with a grinding liquid. The colorant is configured to be added to a first paint base to form a first paint. The first paint has the property that when the first paint is added to a second paint made from the same paint base as the first paint, a third paint is formed, wherein the chroma of the third paint is less than the chroma of the second paint, and the hue and value of the third paint are substantially the same as the hue and value of the second paint. Advantageously, the xe2x80x9ccomponent ratiosxe2x80x9d of the various constituent colorants to the base in the third paint can be readily determined from the quantities of such colorants and the base in the first and second paints. Such component ratios may then be used subsequently to recreate the paint color of the third paint.
In another aspect, the present invention provides a method of producing a paint, comprising the steps of blending a mixture of pigments with a grinding liquid to form a neutral paint colorant, adding the neutral paint colorant to a first paint base to form a first paint, and adding a volume of the first paint to a volume of a second paint to form a third paint. The neutral paint colorant has the property such that the chroma of the third paint is less than the chroma of the second paint, and the hue of the third paint is substantially equal to the hue of the second paint. Further, the addition of the neutral paint colorant to the first paint base may be controlled so that the first paint has a value substantially equal to the value of the second paint.
In another aspect, the present invention provides a paint colorant comprising 6.3% to 7.7% Color Index Pigment Yellow 42, 2.16% to 2.64% Color Index Pigment Red 101, and 3.6% to 4.4% Color Index Pigment Black 7. In a narrower aspect, the paint colorant comprises 7.0% Color Index Pigment Yellow 42, 2.4% Color Index Pigment Red 101, and 4.0% Color Index Pigment Black 7. The remainder of the paint colorant comprises components other than pigments, such as a grinding liquid.
In another aspect, the present invention provides a method of producing a neutral paint colorant, comprising the steps of blending Color Index Pigment Yellow 42, Color Index Pigment Red 101, and Color Index Pigment Black 7 together to form a pigment mixture, and blending the pigment mixture into a grinding liquid to form a paint colorant. The paint colorant has a composition of 6.3%-7.7% Color Index Pigment Yellow 42, 2.16%-2.64% Color Index Pigment Red 101, and 3.6%-4.4% Color Index Pigment Black 7.
In another aspect, the present invention provides a method of creating a paint, comprising the steps of selecting a source paint comprising a mixture of paint colorants with a first paint base, blending a neutral paint colorant with a second paint base to form a neutral paint, and blending the neutral paint with the source paint to form an output paint. The neutral colorant comprises 6.3% to 7.7% Color Index Pigment Yellow 42, 2.16% to 2.64% Color Index Pigment Red 101, and 3.6% to 4.4% Color Index Pigment Black 7. The first and second paint bases are identical. The hue and value of the created output paint are substantially equal to the hue and value of the source paint, and the chroma of the created output paint is less than the chroma of the source paint.
In another aspect, the present invention provides a device for blending paint colorants with a paint base to create an architectural paint having a desired hue, value, and chroma. The device comprises a plurality of spouts adapted to eject a paint colorant, wherein one of the spouts is adapted to eject a neutral paint colorant. In one embodiment, the neutral paint colorant comprises 6.3% to 7.7% Color Index Pigment Yellow 42, 2.16% to 2.64% Color Index Pigment Red 101, and 3.6% to 4.4% Color Index Pigment Black 7.
All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description having reference to the attached figures, the invention not being limited to any particular embodiment(s) disclosed.